create "common" section in API docs

.verb.md

@@ -48,6 +48,68 @@ var app = templates();
 ```
 
 ## API
+### Common
+This section describes API features that are shared by all Templates classes.
+
+#### .option
+
+Set or get an option value.
+
+**Params**
+
+* `key` **{String|Object}**: Pass a key-value pair or an object to set.
+* `val` **{any}**: Any value when a key-value pair is passed. This can also be options if a glob pattern is passed as the first value.
+* `returns` **{Object}**: Returns the instance for chaining.
+
+**Example**
+
+```js
+app.option('a', 'b');
+app.option({c: 'd'});
+console.log(app.options);
+//=> {a: 'b', c: 'd'}
+```
+
+#### .use
+
+Run a plugin on the given instance. Plugins are invoked immediately upon instantiating in the order in which they were defined.
+
+**Example**
+
+The simplest plugin looks something like the following:
+
+```js
+app.use(function(inst) {
+  // do something to `inst`
+});
+```
+
+Note that `inst` is the instance of the class you're instantiating. So if you create an instance of `Collection`, inst is the collection instance.
+
+
+**Params**
+
+* `fn` **{Function}**: Plugin function. If the plugin returns a function it will be passed to the `use` method of each item created on the instance.
+* `returns` **{Object}**: Returns the instance for chaining.
+
+**Usage**
+
+```js
+collection.use(function(items) {
+  // `items` is the instance, as is `this`
+
+  // optionally return a function to be passed to
+  // the `.use` method of each item created on the
+  // instance
+  return function(item) {
+    // do stuff to each `item`
+  };
+});
+```
+
+### Application
+This section describes the methods and features available on the main `Templates` class.
+
 {%= apidocs("index.js", {type: 'app', ctor: 'templates'}) %}
 
 
@@ -67,6 +129,8 @@ var app = templates();
 ***
 
 ### View
+API for the `View` class.
+
 {%= apidocs("lib/view.js") %}
 
 #### Settings
@@ -78,6 +142,8 @@ var app = templates();
 ***
 
 ### Item
+API for the `Item` class.
+
 {%= apidocs("lib/item.js") %}
 
 #### Settings
@@ -89,6 +155,8 @@ var app = templates();
 ***
 
 ### Collections
+API for the `Collections` class.
+
 {%= apidocs("lib/collection.js") %}
 
 #### Settings
@@ -100,6 +168,8 @@ var app = templates();
 ***
 
 ### List
+API for the `List` class.
+
 {%= apidocs("lib/list.js") %}
 
 #### Settings
@@ -108,6 +178,8 @@ var app = templates();
 ***
 
 ### Group
+API for the `Group` class.
+
 {%= apidocs("lib/group.js") %}